Valve.



N o. 685,748. Patented Nov. 5, mm.

a. MQDAVIS.

VALVE. (Application ma m 15, 901.

(No Model.)

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UNIT D STATES PATENT OFFICE.

GEORGE M. DAVIS, OF CHICAGO, ILLINOIS.

VALv.

part of Letters Patent 0. 685,748, dated Ilovember 5, 196i.

Application filed Ma 15,1901. sum No. 60,323. (No model.)

To all whom it may ooitcerit; v I

Be it known that I, GEORGE M. DAVIS, a citizen of the United-States, residing in Ohicage, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Valves, of which the followin is a specification.

31y invention relates to valves, and has for its object to provide means whereby the tendency of valves used, for example, in connection with steam-heatin g to leak maybe minimized.

One form. of my invention, or a form of valve in which my invention may be found, is illustrated in the accompanying drawing, wherein is shown a vertical cross-section through a valve body audstem.

A isthe discharge end internally screwthreaded to receive, for example, the end of the pipe leading to the radiator in the steam heating plant.

B is the supply end of-the valve, in like manner internally screw-threaded to receive the end of the steam-supply pipe in such steam heating plant.

'0 is a valve-seat in the body of the valx e and surrounding the opening through which a connection ismadetbetween the supply and the discharge ends of the valve.

D is a valve-face, preferably of some kind of composition, which impinges upon the valve-seat to close the opening referred to. This valve-face takes the form of an annulus seated within the outer ring-like ledge E on the disk F. From this disk projects the lower end G, externally screw-threaded, and H is a thimble provided with the annular flange J, the thimble being screw-threaded to engage the screw-threads on the part G and the flange being adapted to take under the edge of the annular valve-face, and thus hold the same securelyin position in connection with the disk F. The disk F is supported from the stem K, which has at its upper end the hand-wheel L, is screw-threaded at M to engage the internally-screw-threaded valve centerpiece N, and is enlarged at its lower extremity 0, so as to form a sort of annularflange, which when the stem is raised engages the lower endof the thimble P, which is screwthreaded into the disk F. Thus the stem and disk of the valve are loosely secured together.

R i's'an internal longitudinal aperture within the valve-stem, which thus becomes a kind of tube, and S is a rod within suchitube', adapt ed at its upper end to seat against a plug T and at its lower end provided with a bearingsurface U, which is enlarged so as to take the form of a disk and which bears against the upper central surfaceot' the valve-disk F. The rod is somewhat loose in the aper ture, and the disk U has a certain amount of free motion up and down in the space between the lower end of the stem 0 and the upper central surface of the disk F; The

cap N is screw-threaded at Vinto the exte- I riorshell W of the valve proper.

X is a cover surrounding the valve-stem and secured to the valve-cap N, and it may serve as a stuifing-box.

I do not wish to be limited to the particular arrangement and form and proportions of the several parts, as it will be obvious to any one that they can be considerably varied without departing from the spirit of my in- The location of the supply and disvention. charge ends or ways of the valve proper might be varied, as also'the position and relation of the valveface and valve-seat.

In the case shown the valve-face is composed of composition which has a coefficient .i

of expansion different from that of the valvebody proper. This composition, however, can

be greatly varied, and it might even be dispensed with, being integral in that case with the valve-disk F. It will be observed inthe construction shown that the valve stem proper does not directly apply pressure to the valve-disk to seat it upon thevalve-seat, but that such pressure is applied indirectly through the internal rod within the tubular valve-stem. This rod has a coefficient of expansion dilTerent from the tubular stem or from that of the valve-shell proper. When the valve has been open and the steamhas been passing through in the direction indicated by the arrow, all the parts will naturally be heated. If new the valve be closed by turning the handle L until the tubular stem is screwed down to the point where the upper extremity of the rod S engages the plug T, a further continuation of the motion of the handle will cause the disk on the lower end of the rod to apply pressure to the valve-disk F above the portion G, and thus force the valve-f ace against the valve-seat and securely close the valve. Now under these conditions naturally the valve begins to cool. Sometimes water may form in the upper portion of the supply way or end B or for other reasons the valve-shell proper and its associated parts may be cooled off to a considerable extent. This tends to loosen the valve, because in the first place the composition commonly employed contracts to a greater degree than the other parts surrounding it. On the other hand, and also if no such composition is used, the contraction of the tubular stem is such as to tend to shorten such stem below the line of its connection with the valve-cap, and if the valve-face were in rigid relation with such stem this action would tend to lift the valveface associated with the stem from the valveseat. At the same time the contraction of the exterior shell of the valve proper, including the cap, is such as to tend also to open the valve and cause the leakage so familiar in valves of this character.

What I desire to accomplish is the equalization by a differential action of the contraction taking place between the valve-face and the point where the stem engages the cap through the valve stem and between the valve-seat and the point where the valve-cap engages the stem through the valve-shell. This I accomplish by providing the inner rod S, which has less power of contraction than the other parts of the valve. The length and the power of contraction of such rod must be varied to accommodate itself to variations in the size and materials of the valve shell, stem, and other parts and also with relation to the peculiarities of the valve-face. These parts are so adjusted that when the cooling action begins the displacement of the valve-face by the contraction of the parts holding or associated with it is approximately equal to the displacement of the valve-seat by the contraction of the parts holding or associated with it. In other words, the contraction of the valve-stem and its associated parts is approximately equal to the contraction of the valve-shell, so that the valve face and seat are retained in their proper relations to each other to close the valve-aperture even after such contraction. The oflice of such internal rod or tube in a case where composition is employed to form the valve-face is more especially to'offset the inequality in the contraction of such composition as compared with other parts of the steam-valve. Where no such composition is used and the construction and relation of the parts are such that the contraction will separate the valve seat and face, then the office of such inner rod or tube is to overcome that inequality.

In regard to the expansion and contraction I describe them as approximately equal in the supports for the valve-seat and valveface, and I mean by this term to indicate that the contraction and expansion shall be such, either a little more or a little less in one or the other side, as to keep the valve and seat from separating and the valve from leaking under the effect of contraction.

I have used the word difierential, and I mean by that to indicate broadly the idea of differences in contraction and expansion between the several parts of a stem in the form in which I have presented it or between the two supports which I have called the valve face and seat. The valve-body may be of brass, the rod within the stem of iron, and the valve-face of suitable composition.

I claim-- 1. In a valve, the combination of a valveshell to which the seat is attached, having a certain range of contraction and expansion between the seat and the point of engagement of the shell with the stem, with astem carrying a valve-face adapted to engage the seatand containing a part having a different capacity for contraction and expansion from that of the shell, the parts of the stem arranged so that the total contraction from the point of engagement of the valve-seat and valve-face through the stem to the engage= ment between the stem and the shell is approximately equal to that through the shell.

2. In a valve, the combination of a valveshell, to which the seat is attached, having a certain range of contraction and expansion between the seat and the point of engagement ,of the shell with the stem, with a stem carrying a valve-face composed of a substance different from the stem and adapted to engage the seat, said stem containing a part having a diiferent capacity for contraction and expansion from that of the shell, the parts of the stem arranged so that the total contraction from the point of engagement ofthe valveseat and valve-face through the stem to the engagement between the stem and the shell is approximately equal to that through the shell.

3. In a valve, the combination of a stem and valve-disk containing two parts, exclusive of the valve-face portion, which are free to move one on the other and are of difierent powers of contraction and expansion,and a surrounding shell of a power of contraction and expansion diiferent from that of one of said two parts.

4:. In a Valve, the combination of a valveseat-supporting part with a valveface-sup porting part, one of said parts composed of substances which differ in their powers of contraction and expansion, and are arranged so that the resultant of the contraction of the substances of such supporting part is approximately equal to the contraction of the other supporting part.

5. Ina valve, the combination of a valveseat with a valve-face, a supporting part for each, an engagement between the two supporting parts, the distances from the point of engagement between the valve and the seat to scans tive position in spite of contraction or expansion.

6. In a valve, the combination of a valveseat with a va1ve-face,, a supporting part for each, an engagement between the two supporting parts, the distances from the point of engagement between thevalve and the seat to the engagement between the two supporting parts through such supporting parts being unequal, a difi'erential contraction and expansion device associated with one supporting part, and arranged so that the contraction of the two supporting parts between their point of engagement and the point of engage ment of the valve and seat is approximately equal, and a composition of which the valveface is formed.

'7. In a valve, the combination of a valveseat with a valve-face, a supporting part for each, an engagement between the two sup porting parts, the distances from the point of engagement between the valve and the seat to the engagement between the two supporting parts through such supporting parts being unequal, adifferential contraction and expansion device associated with one supporting part, and arranged so that the contraction of the two supporting parts between their point of engagement and the point of engagement of the valve and seat is approximately equal, said differential contraction and expansion device containing a tube and a rod or tube within the same of diflerent coefficients of expansion.

8. In a valve, a valve-seat in combination with a valve-stem, a valve-disk carrying a face which engages the seat, said valve-disk loose upon the stem, and a rod or tube within the stem and projecting beyond the same so as to engage the upper middle surface of the valve-disk, said tubular valve-stem and the rod or tube having difierent coefficients of expansion.

9. In a valve, a valve-seat in combination with a valve-disk carrying a face which engages the seat, said valve-disk associated with a rod which extends up loosely into the valvestem to its point of effective engagement therewith, said rod having a coefficient of expansion diifering from that of the material 66 forming a portion of the valve and stem.

10. In a valve, the combination of a valve: seat-supporting part with a valve-face-supporting part and a valve face formed of a com position, said composition and valve-facesupporting part difiering in their powers of contraction and expansion, and arranged so that the resultant of the contraction of such composition and face-supporting part is approximately equal to the contraction of the 76 valve-seat supporting part.

11. In a valve, the combination of a valveseat-supporting part with a valve -face-supporting part, and a difierential contract-ion and expansion device associated with a supporting part, so that the contraction of the two supporting parts between their point of engagement and the point of engagement of the valve and seat is approximately equal.

12. In a valve, the combination of a valve- 80 seat-supporting part with a valve face -supporting part, the valve-face-supporting part containing a valve disk and stem, and a differential contraction and expansion device associated therewith.

GEORGE M. DAVIS. 

